When any construction, reconstruction, or maintenance of a public road, highway, street, or airport is undertaken by the state or any political subdivision in the state and public funds of the United States, state, or any political subdivision are directly used for the purchasing of motor vehicle fuel to be used in publicly owned vehicles for such construction, reconstruction, or maintenance, such motor vehicle fuel is subject to a refund of the tax paid on the fuel as provided for in this chapter and under the same terms and conditions. The refund provided for in this section may not be reduced for deposit to the agricultural products utilization fund.